Five Troubleshooting Tips For Your Furnace Blower
Posted on: 7 August 2020
Your furnace can only warm your home if the heated air is blown through the vents to circulate. For this task, your furnace needs an operating blower fan. The following can help you troubleshoot the furnace if the fan isn't coming on.
1. Test the Blower Fan
Start by verifying that the blower has actually failed. To do this, turn the furnace setting from "on" to the "fan only" setting on the thermostat. Within a moment or two, you should hear the fan pop on and cool air should begin coming from the vents. If the fan does turn on, then problem isn't with the blower. Instead, you may be getting poor heat due to burner issues or other problems in the furnace. If the fan doesn't come on, then you can troubleshoot to see if it is an easily fixed problem.
2. Check the Circuit Breaker
Your furnace is likely on its own dedicate fuse inside the breaker box. Locate this fuse switch and move it all the way to the off position. Wait a few moments, then move it back to the on position. If the fuse switch feels soft, as though it won't go all the way into place, you may need to have it replaced. Otherwise, if the fuse switches on and stays on, but the fan still won't come on, there is likely another problem.
3. Replace the Filter
A dirty filter can actually cause the fan to malfunction. When the filter becomes clogged with dirt, air can't be pulled into the furnace. This lack of air flow can cause the blower motor to overheat, which will trip a safety switch and shut down the motor so that it doesn't become damaged. If the filter is badly soiled, you may also need to dust out the filter housing to remove the excess debris so that the fan can function again.
4. Test the Thermostat
Thermostat failure is relatively common, particularly if you have an older model. Try turning the thermostat down to the lowest temperature setting. If the furnace pops on, then the thermostat may need to be calibrated or replaced so that it reads the temperature more accurately. If the furnace still won't function, you can use a multimeter to test that electricity is reaching the thermostat or you can bring in a furnace tech to test the thermostat.
5. Call for Repairs
Sometimes the blower fails because the motor is damaged. Lack of routine maintenance is the main cause of this issue. Failure to lubricate bearings and moving parts, to clean the motor assembly, and to tune up everything can cause the motor to burn out.
Contact a furnace repair service if you need more help.
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